So the design was still halfway between an M4A3 and and M4...
Anyway, I welcome a Rubicon Firefly. As I've said a few times, a Hybrid Firefly would be even better, as it was (IMO) the best looking Firefly type. While this would duplicate the recent Warlord Sherman Vc, I think there's room for Rubicon to do it better. I picked up Warlord's Firefly recently, and it's very much a scaled up 15m model, with quite heavy-handed detail. It will probably paint up well, but it verges on WH40k levels of chunkiness. It's a very complete model, however, with spare tracks, spare wheels, a jerrycan, a choice of 2 commander half-figures (which are also obviously scaled-up from 15mm and look a bit odd) and even sand skirts and a Cullin hedgegrow device. So it's a good wargaming model, but a mediocre scale model. I'm sure Rubicon's will be more accurate, and better detailed. But Rubicon will also need to provide at least the same level of extras. Hopefully by then crew figures will be standard in Rubicon kits.